The field of the disclosure relates generally to additive manufacturing systems and, more specifically, to imaging devices for use with additive manufacturing systems and methods of monitoring and inspecting additive manufacturing components.
Additive manufacturing systems and processes are used to fabricate precision three-dimensional components from a digital model. Such components are fabricated using an additive process, where successive layers of material are solidified one on top of the other. At least some known additive manufacturing systems use a laser (or similar energy sources) and a series of lenses and mirrors to direct the laser over a powdered material in a pattern provided by a digital material. Some known additive manufacturing systems include Direct Metal Laser Melting (DMLM), Selective Laser Sintering (SLS), Direct Metal Laser Sintering (DMLS), Selective Laser Melting (SLM) and LaserCusing systems.
In some known additive manufacturing systems, layer and component quality is reduced due to variation in heat being transferred to the metal powder by the focused laser within the melt pool. For example, sometimes undesirable features such as air pockets, internal voids, and/or cracking occur within and/or between build layers. In addition, in some known additive manufacturing systems, heat variation also induces porosity within the build layers. Moreover, variation in laser position is also known to generate these undesirable features within the additively manufactured component.
At least some known additive manufacturing systems include imaging devices that generate images of portions of the melt pool during the fabrication process. The imaging devices typically include a static camera with low exposure that tracks the focused laser to capture light during the melting process. However, the imaging devices generate images of only visible portions of the component and thus do not capture subsurface features. Other known component inspection techniques include ultrasound and x-ray imaging. However, ultrasound imaging requires that the component be finished, thus further expending time and materials costs for a potentially undesirable part. Additionally, x-ray imaging is typically performed by a digital x-ray or Computer Tomography (CT) scans which are limited by the size of the component and also requires a large amount of x-ray energy to penetrate the entire component. When undesirable features are located, at least some known processes, such as Hot Isostatic Pressing (HIP), attempt to cure the features by re-heating the completed component under pressure. However, not all features, for example, cracking features, are correctable by HIP.